Magnesium Chloride (road de-icer) bad for disc brake pads?

We recently went for a ride which included some road riding on surfaces treated with Magnesium Chloride for de-icing. At the end of the ride, I noticed that my rear brakes (08 XTR with Resin and Metallic pad combo) were kinda weak. I cleaned the rotors and the pads with rubbing alcohol and sanded the pads lightly but the power did not return. Since the pads were about 90% worn, I replaced it (using the same resin and metallic combo) and the power was back (it still needs to be bedded in however).
I'm not quite sure if it was the Mag Chloride or the slush with possibly road oils that got thrown up onto my rotors/pads that caused the contamination (or both)...
Has anyone experienced this or know any reason why de-icer would cause contamination?
Thanks...

I read an article in a trucking magazine talking about the new de-icer that was being used on the roads. This is nasty stuff. It will corrode aluminum, copper and just about anything else. It was also causing the friction material to separate from the backing plate on brake shoes.

Flip,
Take a look at a Periodic chart of Elements. Look at where Natrium (sodium) and Magnesium is and what their ionic number is. Then look at the other side of the chart and looks at Chlorine and Oxygen and what their ionic number is. Then take a look at Oxidation /reduction charts to determine chemical reactions and the hierarchy which is more chemically reactive than others.

All those chemically reactive salt and salt like elements are bad, bad, really bad juju for anything made out of steel, copper or aluminum in them, like your brake pads, rotors, hydralic cylinder etc. They are corrosive.

I'd pass on riding salted roads. It gets spray in and on everything, and wrecks it.